Attachment bracket

ABSTRACT

A bracket for attaching at least one vibrator to an ice basket of a pressurized water reactor includes a horizontally extending first armature portion and a horizontally extending second armature portion pivotably attached to the second armature portion. The first and second armature portions have clamps extending downwardly from each of their ends, and each of the clamps includes an arcuate groove extending vertically upwardly from its bottom surface to engage the rim of the ice basket. An attachment portion extends vertically upwardly from and is formed unitarily with the first armature portion, the vibrators being attached to the sides of the attachment portion. The clamps extending from the second armature portion are pivotably connected to and are also laterally adjustable with respect to the first and second ends of the second armature portion.

This application is a divisional of U.S. patent application Ser. No.08/235,707, filed Apr. 29, 1994 now U.S. Pat. No. 5,456,532.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to ice condensers for pressurized waternuclear reactors and to methods of maintaining the ice in such icecondensers. More specifically, the invention relates to a vibratingassembly for vibrating the ice baskets of an ice condenser of apressurized water reactor, and to a method of maintaining the ice in theice baskets using such a vibrating assembly.

2. Related Art

There are two types of nuclear reactors generally used in the UnitedStates, the boiling water reactor and the pressurized water reactor. Incommercial nuclear plants, the reactor is housed in a building called acontainment structure. In a catastrophic accident in which one of thepipes attached to the reactor breaks, the contents of the pipe arereleased into the containment structure.

In boiling water reactors, steam released in the event of a catastrophicaccident fills the containment structure and then is forced into a poolof water, so as to suppress the steam and reduce the pressure in thecontainment structure.

In pressurized water reactors, the reactor is housed in a large "dry"containment structure. The size and strength of the containment holdsthe steam in the event of an accident. However, in one version of apressurized water reactor, a suppression system is included to condensesteam released during an accident. This suppression system is known asan ice condenser, and was developed by Westinghouse ElectricCorporation. An early example of such a suppression system is thesubject of U.S. Pat. No. 3,580,806 to Weems et al and assigned toWestinghouse.

In the ice condenser suppression system, fragmented ice is maintained inbaskets located in the containment structure. In the event of anaccident, the steam released from a broken pipe is channeled into theice baskets to reduce the pressure in the containment and prevent therelease of radioactive steam outside the containment.

Due to melting and sublimation, voids tend to form in the body offragmented ice, and pieces of fragmented ice may become fused together.In order to minimize these problems, Weems et al propose a system forreducing the thermal gradients, and in turn the convection currents towhich the ice fragments are exposed. However, even with such a system,melting and sublimation cannot be eliminated. Consequently, the priorart has developed a number of systems for maintaining the bodies offragmented ice. U.S. Pat. Nos. 3,850,002; 4,659,068; 4,671,920;4,711,755; and 4,723,611 are illustrative of such systems. These systemstend to be mechanically complicated, and to be directed to recharging orreplenishing the supply of ice, rather that maintaining the ice inoptimum condition so as to delay the need for recharging.

It is to the solution of these and other problems to which the presentinvention is directed.

SUMMARY OF THE INVENTION

It is therefore a primary object of the invention to provide a systemfor freeing the ice in the ice baskets of an ice condenser suppressionsystem, thereby maintaining the ice in optimum condition and making itmore effective.

It is another object of the invention to provide a method formaintaining the ice in the ice baskets of an ice condenser suppressionsystem which employs vibration to free the ice in the ice baskets.

These and other objects of the invention are achieved by providing avibrating assembly for vibrating an ice basket of a pressurized waterreactor which comprises first and second vibrators and a bracketoperatively connected to the vibrators. The bracket includes ahorizontally extending first armature portion and a horizontallyextending second armature portion pivotably attached at its center tothe bottom center of the second armature portion. The first armatureportion has first and second clamps extending downwardly from its firstand second ends, respectively, while the second armature portion hasthird and fourth clamps extending downwardly from its first and secondends, respectively. Each of the clamps includes a groove extendingvertically upwardly from its bottom surface.

The bracket further includes an attachment portion extending verticallyupwardly from the first armature portion, the vibrators being attachedto the sides of the attachment portion. In one aspect of the invention,the attachment portion is unitarily formed in a single, generallyT-shaped piece with the first armature portion. Further, the bracket issmoothly rounded where the attachment portion joins the first armatureportion, thereby distributing concentrated forces due to vibrationswhere the bracket and the first armature portion join.

In another aspect of the invention, the third and fourth clamps arepivotably connected to the first and second ends, respectively, of thesecond armature portion; and are also laterally adjustable with respectto the first and second ends of the second armature portion towards andaway from the middle of the second armature portion.

In still another aspect of the invention, the grooves formed in theclamps are arcuate, having a radius matching the curvature of the rim ortop ring of the ice basket.

In the method in accordance with the invention, the vibrator assembly isattached to the rim or top ring of the ice basket by adjusting thepositions of the third and fourth clamps to fit the rim and thensecuring the rim in the first, second, third, and fourth clamps. Thevibrators are then activated to free the ice in the ice basket. Whilethe vibrators are activated, the ice basket is pulled from above byexerting an upward force on the bracket and is pushed from below toexert a combination of tension and compression on the ice basket.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is better understood by reading the following DetailedDescription of the Preferred Embodiments with reference to theaccompanying drawing figures, in which like reference numerals refer tolike elements throughout, and in which:

FIG. 1 is a perspective view of an attachment bracket in accordance withthe present invention, as secured to an ice basket in use.

FIG. 2 is a top plan view of the assembly of FIG. 1.

FIG. 3 is an exploded perspective view of the bracket of the vibratingassembly.

FIG. 4 is a diagrammatic representation of the vibrating assembly ofFIG. 1 secured to an ice basket, with the ice basket being pulled fromthe top and pushed from the bottom in accordance with the method of theinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In describing preferred embodiments of the present invention illustratedin the drawings, specific terminology is employed for the sake ofclarity. However, the invention is not intended to be limited to thespecific terminology so selected, and it is to be understood that eachspecific element includes all technical equivalents which operate in asimilar manner to accomplish a similar purpose.

Referring now to FIGS. 1-3, there is shown a vibrating assembly 10 inaccordance with the present invention for vibrating an ice basket 20 ofa pressurized water reactor (not shown). Vibrating assembly 10 comprisesleft and right vibrators 100a and 100b and a bracket 200 for operativelyconnecting vibrators 100a and 100b to the rim or top ring 20a of an icebasket 20.

Bracket 200 includes a horizontally-extending first armature portion 210having first and second downwardly-extending ends 212 and 214 and amiddle 216 intermediate first and second ends 212 and 214. First andsecond clamps 220 and 222 extend downwardly from first armature portion210 at first and second ends 212 and 214. First and second clamps 220and 222 are welded or otherwise fixed at notches cut out of first andsecond ends 212 and 214, respectively.

An attachment portion 230 extends vertically upwardly from firstarmature portion 210. Attachment portion 230 is unitarily formed in asingle, generally T-shaped piece with first armature portion. 210.Preferably, first armature portion 210 and attachment portion 230 areformed from a 3/4" thick piece of metal plate. Junctions 232 betweenattachment portion 230 and first armature portion 210 are smoothlyrounded to distribute forces concentrating at junctions 232 due tovibrations. A hole 234 is drilled proximate the top center of attachmentportion 230 to accommodate a lifting shackle (not shown) used inplacement and removal of assembly 10.

Bracket 200 further includes a horizontally-extending second armatureportion 240 pivotably connected to the bottom of a first armatureportion 210. Second armature portion 240 has first and secondoutwardly-extending ends 242 and 244 and a middle 246 intermediate firstand second ends 242 and 244. Third and fourth clamps 250 and 252 extenddownwardly from second armature portion 240 at first and second ends 242and 244, respectively. Third and fourth clamps 250 and 252 are pivotablyconnected to first and second ends 242 and 244 in a manner to bedescribed in detail hereinafter.

Each of first and second clamps 220 and 222 and third and fourth clamps250 and 252 has top and bottom surfaces 260 and 262, inner and outersurfaces 262 and 264, and opposed end surfaces 268. A groove 270 extendsvertically upwardly from each bottom surface 262 and across each ofclamps 220, 222, 250, and 252 from one to the other of end surfaces 268.Grooves 270 are arcuate, having a radius matching the curvature of rim20a of ice basket 20.

An internally-threaded cylindrical bore 272 extends inwardly from eachinner surface 264 so as to be in communication with each groove 270. Asocket head cap screw 274 or similar fastener is inserted into each bore272 With a locking washer 276 interposed between its head and innersurface 264 in a conventional manner to secure rim 20a in groove 270 inthe same manner as a set screw. As will be appreciated by those ofordinary skill in the art, bore 272 can equally well extend from outersurface 266 into communication with groove 270.

The manner in which third and fourth clamps 250 and 252 are connected tosecond armature portion 240 will now be described. First and second ends242 and 244 of second armature portion 240 are provided with first andsecond vertically-extending slots, respectively. Socket head cap screws286 or similar fasteners are inserted through slots 282 and 284 and intobores 280 of third and fourth clamps 250 and 252, with locking washers288 conventionally interposed between the screw heads and top surfaces260 of third and fourth clamps 250 and 252. The lateral positions ofscrews 286 in first and second slots 282 and 284 are adjustable. Theangular position of grooves 270 of third and fourth clamps 250 and 252with respect to the longitudinal axis of second armature portion 240 arealso adjustable by pivoting third and fourth clamps 250 and 252 relativeto the longitudinal axis of second armature portion 240 beforetightening screws 286.

In order to connect second armature portion 240 to first armatureportion 210, first armature portion 210 is provided with aninternally-threaded bore 290 extending upwardly at its center bottom,while second armature portion 240 is provided with a bore 292 throughits center. With bores 290 and 292 aligned, a socket head cap screw 294or similar fastener is inserted through bores 292 and 290 to pivotallyconnect first and second armature portions 290 and 292 at theirrespective middles 216 and 246. Again, a locking nut 296 isconventionally interposed between the screw head and the bottom ofsecond armature portion 240.

Preferably, left and right vibrators 100a and 100b are air poweredvibrators such as CCR 5500 Martin Vibrotor™ vibrators, and attachmentportion 230 is approximately 5" wide by 12" high to accommodate themounts 110, such as Cradle lug clamp mounts (part no. 22817) required toclamp vibrators 100a and 100b to the sides of attachment portion 230.Vibrators 100a and 100b and their mounts 110 are bolted on each side ofattachment portion 230 in the vertical position. This arrangementprovides counter rotation of vibrators 100a and 100b and enhances thevibrating efficiency. When in operation, the vibrating forces aredirected down along the sides of ice basket 20.

Also preferably, plant air at 60-80 psig is utilized with two airseparator-dryers (not shown) to operate vibrators 100a and 100b,producing a total output of approximately 25 CFM. Although thisarrangement has proven successful in experimental trials, increasing thetotal output to 30-50 CFM is also contemplated. It is hypothesized thatthe additional air supply would increase the vibrating forcestransferred to each ice basket 20 and therefore shorten the timeinterval required to vibrate each ice basket.

In use, as indicated above, a lifting shackle (not shown) is attached toattachment portion 230 through hole 234 in order to position vibratingassembly 210 over the top of a selected ice basket 20. Once vibratingassembly 10 is properly oriented with rim 20a of ice basket 20 properlyseated within grooves 270, cap screws 274 are tightened to securevibrating assembly 10 to ice basket 20. Screw 294 fastening secondarmature portion 240 to first armature portion 210, and screws 286fastening clamps 250 and 252 to second armature portion 240 are thentightened to complete the installation of vibrating assembly 10. Onceall of the screws have been checked for tightness, the air supply can beturned on to start vibrators 100a and 100b.

Referring now to FIG. 4, in order to optimize the vibrating capabilitiesof vibrators 100a and 100b, ice basket 20 is pulled from the toputilizing either an overhead hoist or a Port-a-Power™ attached to afabricated A-frame, depending on the overhead clearance available. Bothmethods utilize a load cell and the maximum tension is maintained atless than or equal to 3000 pounds pressure. Ice basket 20 also is pushedfrom the bottom utilizing a Port-a-Power™ with a load cell to maintain acompression of less than or equal to 4000 pounds pressure. Thecombination of tension and compression during the vibrating maximizesthe vibrations along the surfaces of ice basket 20.

Modifications and variations of the above-described embodiments of thepresent invention are possible, as appreciated by those skilled in theart in light of the above teachings. For example, hold down clamps maybe used in certain situations to fit over ends 212, 214, 242, and 244and to extend through the basket 20 below the top ring to prevent theassembly 10 from pulling off of the top ring.

It is therefore to be understood that, within the scope of the appendedclaims and their equivalents, the invention may be practiced otherwisethan as specifically described.

What is claimed is:
 1. A bracket for attaching at least one vibrator toan ice basket of a pressurized water reactor, comprising:a horizontallyextending first armature portion having first and second ends and amiddle intermediate said first and second ends; first and second clampsextending downwardly from said first armature portion at said first andsecond ends thereof, respectively, said first and second clamps eachhaving a bottom surface and including an arcuate groove extendingvertically upwardly from said bottom surface; a horizontally extendingsecond armature portion having first and second ends and a middleintermediate said first and second ends, said second armature portionbeing pivotably connected to said first armature portions at saidmiddles thereof; and third and fourth clamps extending downwardly fromand pivotably connected to said second armature portion at said firstand second ends thereof, respectively, said third and fourth clamps eachhaving a bottom surface and including an arcuate groove extendingvertically upwardly from said bottom surface.
 2. The bracket of claim 1,further comprising an attachment portion extending vertically upwardlyfrom said first armature portion, said at least one vibrator beingattached to said bracket at said attachment portion.
 3. The bracket ofclaim 2, wherein said attachment portion is unitarily formed in asingle, generally T-shaped piece with said first armature portion. 4.The bracket of claim 3, wherein said bracket is smoothly rounded wheresaid attachment portion joins said first armature portion, therebydistributing concentrated forces due to vibrations where said bracketand said first armature portion join.
 5. The bracket of claim 1, whereinsaid third and fourth clamps are laterally adjustable with respect tosaid first and second ends of said second armature portion towards andaway from said middle of said second armature portion.
 6. The bracket ofclaim 1, wherein the ice basket has a rim having a curvature, andwherein said grooves are arcuate, having a radius matching the curvatureof the rim of the ice basket.